Humans with damage to primary visual cortex (V1) are for most purposes blind, although in some circumstances they can "guess" accurately about stimuli they do not consciously see (blindsight); if the damage occurs early in life recovery can be very good and include some awareness of stimuli and ability to discriminate direction of motion. This project assesses the role of cells in the visual thalamus in the improved recovery via a monkey model of neurophysiological and anatomical changes. This year, additional subjects with V1 damage were prepared for single-unit recording and anatomical studies. In addition, using anatomical techniques in normal subjects, we found a clear absence of a transient pathway between the geniculate and cortical areas involved in visual motion processing early in life, a pathway which is present in the cat and which contributes to recovery of vision after cortical damage in that species. This result rules out one possibility for the ne ural basis of the improved recovery, and argues against the assumption that visual mechanisms are similar in detail in other mammals and monkeys. Clearly, monkeys are required to draw insights about primate nervous systems. FUNDING NSF IBN-9723178 $45,960 9/01/97 - 8/31/00 PUBLICATIONS Moore, T., Rodman, H.R. and Gross, C.G. Man, monkey and blindsight. The Neuroscientist 4:227-230, 1998.